Disease protection (#4524)

# About the pull request
Wearing mask/latex gloves/bio suit/space suit will now impact the
likeliness of you getting infected from flu/cold/whatever. Doesnt affect
black goo(zombie)

I also have absolutely no idea what Astar proc is and why its there so I
replaced that with adjacent. UPD: astar returned. its pathfinding.

Nuked one single letter var so be happy
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# Explain why it's good for the game
More interesting moments with those events of flu disease once in a
decade, like mask and gloves distribution.(perhaps we will have more of
them now)
Plus I was so sad that wearing new cool biosuit doesn't protect you from
it.
Wearing full kit wont give 100% immunity, final random roll always does
-5
# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>

Put screenshots and videos here with an empty line between the
screenshots and the `<details>` tags.

</details>


# Changelog
:cl: Kivts
add: You can partially protect yourself from flu and other disease by
wearing a mask and other PPE. Doesnt affect Black Goo.
/:cl:

code/datums/disease.dm

@@ -121,10 +121,10 @@ var/list/diseases = typesof(/datum/disease) - /datum/disease
 		check_range = 1 // everything else, like infect-on-contact things, only infect things on top of it
 
 	if(isturf(source.loc))
-		for(var/mob/living/carbon/M in oview(check_range, source))
-			if(isturf(M.loc))
-				if(AStar(source.loc, M.loc, /turf/proc/AdjacentTurfs, /turf/proc/Distance, check_range))
-					M.contract_disease(src, 0, 1, force_spread)
+		for(var/mob/living/carbon/victim in oview(check_range, source))
+			if(isturf(victim.loc))
+				if(AStar(source.loc, victim.loc, /turf/proc/AdjacentTurfs, /turf/proc/Distance, check_range))
+					victim.contract_disease(src, 0, 1, force_spread)
 
 	return
 
@@ -173,8 +173,6 @@ var/list/diseases = typesof(/datum/disease) - /datum/disease
 		var/mob/living/carbon/human/H = affected_mob
 		H.med_hud_set_status()
 
-
-
 /datum/disease/New(process=TRUE)//process = 1 - adding the object to global list. List is processed by master controller.
 	cure_list = list(cure_id) // to add more cures, add more vars to this list in the actual disease's New()
 	if(process)  // Viruses in list are considered active.

code/datums/diseases/mob_procs.dm

@@ -80,9 +80,6 @@
 
 	passed = check_disease_pass_clothes(target_zone)
 
-	if(!passed && spread_type == AIRBORNE && !internal)
-		passed = (prob((50*virus.permeability_mod) - 1))
-
 	if(passed)
 		AddDisease(virus)
 
@@ -111,36 +108,39 @@
 
 /mob/living/carbon/human/check_disease_pass_clothes(target_zone)
 	var/obj/item/clothing/Cl
+	var/protection = 0
 	switch(target_zone)
 		if(1)
 			if(isobj(head) && !istype(head, /obj/item/paper))
 				Cl = head
-				. = prob((Cl.permeability_coefficient*100) - 1)
-			if(. && wear_mask)
-				. = prob((Cl.permeability_coefficient*100) - 1)
+				protection += (Cl.permeability_coefficient*100)-100
+			if(isobj(wear_mask))
+				Cl = wear_mask
+				protection += (Cl.permeability_coefficient*100)-100
 		if(2)//arms and legs included
 			if(isobj(wear_suit))
 				Cl = wear_suit
-				. = prob((Cl.permeability_coefficient*100) - 1)
-			if(. && isobj(WEAR_BODY))
+				protection += (Cl.permeability_coefficient*100)-100
+			if(isobj(WEAR_BODY))
 				Cl = WEAR_BODY
-				. = prob((Cl.permeability_coefficient*100) - 1)
+				protection += (Cl.permeability_coefficient*100)-100
 		if(3)
 			if(isobj(wear_suit) && wear_suit.flags_armor_protection & BODY_FLAG_HANDS)
 				Cl = wear_suit
-				. = prob((Cl.permeability_coefficient*100) - 1)
+				protection += (Cl.permeability_coefficient*100)-100
 
-			if(. && isobj(gloves))
+			if(isobj(gloves))
 				Cl = gloves
-				. = prob((Cl.permeability_coefficient*100) - 1)
+				protection += (Cl.permeability_coefficient*100)-100
 		if(4)
 			if(isobj(wear_suit) && wear_suit.flags_armor_protection & BODY_FLAG_FEET)
 				Cl = wear_suit
-				. = prob((Cl.permeability_coefficient*100) - 1)
+				protection += (Cl.permeability_coefficient*100)-100
 
-			if(. && isobj(shoes))
+			if(isobj(shoes))
 				Cl = shoes
-				. = prob((Cl.permeability_coefficient*100) - 1)
+				protection += (Cl.permeability_coefficient*100)-100
 		else
 			to_chat(src, "Something bad happened with disease target zone code, tell a dev or admin ")
+	return prob(clamp(protection, 5, 90))
 

code/modules/clothing/gloves/miscellaneous.dm

@@ -46,7 +46,7 @@
 	icon_state = "latex"
 	item_state = "lgloves"
 	siemens_coefficient = 0.30
-	permeability_coefficient = 0.01
+	permeability_coefficient = 0.35
 
 /obj/item/clothing/gloves/botanic_leather
 	desc = "These leather gloves protect against thorns, barbs, prickles, spikes and other harmful objects of floral origin."

code/modules/clothing/masks/gasmask.dm

@@ -11,7 +11,7 @@
 	w_class = SIZE_SMALL
 	item_state = "gas_alt"
 	gas_transfer_coefficient = 0.01
-	permeability_coefficient = 0.01
+	permeability_coefficient = 0.9
 	armor_melee = CLOTHING_ARMOR_NONE
 	armor_bullet = CLOTHING_ARMOR_NONE
 	armor_laser = CLOTHING_ARMOR_NONE

code/modules/clothing/masks/miscellaneous.dm

@@ -17,7 +17,7 @@
 	flags_inventory = COVERMOUTH
 	flags_armor_protection = 0
 	gas_transfer_coefficient = 0.90
-	permeability_coefficient = 0.01
+	permeability_coefficient = 0.3
 	armor_melee = CLOTHING_ARMOR_NONE
 	armor_bullet = CLOTHING_ARMOR_NONE
 	armor_laser = CLOTHING_ARMOR_NONE

code/modules/clothing/suits/bio.dm

@@ -3,7 +3,7 @@
 	name = "bio hood"
 	icon_state = "bio"
 	desc = "A hood that protects the head and face from biological contaminants."
-	permeability_coefficient = 0.01
+	permeability_coefficient = 0.2
 	armor_melee = CLOTHING_ARMOR_NONE
 	armor_bullet = CLOTHING_ARMOR_NONE
 	armor_laser = CLOTHING_ARMOR_NONE
@@ -30,7 +30,7 @@
 	item_state = "bio_suit"
 	w_class = SIZE_LARGE//bulky item
 	gas_transfer_coefficient = 0.01
-	permeability_coefficient = 0.01
+	permeability_coefficient = 0.2
 	flags_armor_protection = BODY_FLAG_CHEST|BODY_FLAG_GROIN|BODY_FLAG_LEGS|BODY_FLAG_FEET|BODY_FLAG_ARMS|BODY_FLAG_HANDS
 	slowdown = 1
 	armor_melee = CLOTHING_ARMOR_NONE